It's all the rage to call people who oppose the cultivation of genetically engineered crops anti-science. But if science is an open enterprise, then it should welcome discussion and challenges to any prevailing idea.

We should, however, remember that in this case genetic engineering of crops is not merely a scientific enterprise; it's big business. A lot of people have a lot to lose if the public rejects genetically engineered foods, often referred to as genetically modified organisms (GMOs). We are not by any measure in the preliminary phases of this technology. We are not considering it or calmly debating it before its release. We have long since been launched into an uncontrolled mass experiment, the results of which are unknown.

Knowledge is admittedly a double-edged sword. One might argue that any scientific advance brings risks. I would agree. Understanding nuclear fission and then nuclear fusion led to the atomic bomb and then the hydrogen bomb.

More than 30 years ago millions of people across the world flocked to the nuclear freeze movement out of fear that newly elected American president Ronald Reagan would seek a nuclear buildup and a confrontation with the Soviet Union. Were these millions anti-scientific or the voice of reason?

Nuclear discoveries also led to the widespread application of nuclear fission as a source of heat for electricity generating plants, the dangers of which have most recently been on display at the Fukushima Daiichi power plant in Japan. The results of our grand nuclear experiment are ongoing.

Opposition to practical applications of scientific discoveries cannot willy nilly be labeled anti-science. We now know how to clone humans, but so far, human society has chosen to prohibit this use of cloning.

The vast majority of those who want GMO foods labeled or their cultivation banned do not advocate an end to genetic research. They are not anti-scientific. They have legitimate concerns about the safety of crops derived from a specific application of this research, both for humans and for the broader environment.

Let's see if the arguments used to label those who oppose GMOs as anti-science make sense.

1. Lots of scientists endorse the safety and promise of GMOs.
This argument was most recently trotted out as a petition directed at Greenpeace, asking the organization to cease its opposition to GMOs and more specifically to what is called Golden Rice, a rice that produces its own Vitamin A. (Vitamin A deficiency remains a problem in parts of Asia).

It is understandable that those involved in a political debate over the regulation and even prohibition of GMOs will seek visible shows of support from others who are like-minded. This is part of the persuasion process.

But does this prove that those who oppose GMOs are anti-science? More to the point, are scientists who question the safety of GMOs anti-science even as they continue their scientific research?

We must be careful to distinguish research designed merely to understand the workings of the physical world from an endorsement of specific applications of our knowledge to products and practices. There is a big difference between science and applied science.

This is where the problem of what a friend of mine calls the Midgley Effect arises. Thomas Midgley Jr. was a renown American chemist in the first half of the 20th century. He was asked to find compounds that could be added to gasoline to reduce "knocking" in engines (which can cause damage). Midgley's solution was tetraethyllead which became the basis for leaded gasoline.

Midgley assured the public that leaded gasoline was safe. In fact, Midgley was given the prestigious William H. Nichols Medal by the American Chemical Society in 1923 for his breakthrough. Despite concerns about the release of lead into the environment and deaths at a pilot plant, the U.S. Surgeon General and the U.S. Public Health Service both concluded that there was no evidence that leaded gasoline would cause human health problems. Thus, yet another uncontrolled mass experiment began with humans as the subjects.

Only unrelated research on the age of the Earth revealed abnormally high levels of lead in the environment which interfered with such age calculations and led to concerns about leaded gasoline--which, of course, was eventually banned.

But Midgley's work on chlorofluorocarbons (CFCs) as refrigerants was probably even more significant. At the time existing refrigerants--fluids that circulate in refrigerators and draw heat away from their interiors--were corrosive or flammable. The industry wanted something that wasn't either.

Midgley's solution was a set of inert compounds that would easily vaporize and recondense called chlorofluorocarbons and that eventually went by the trade name Freon.

Nonflammable, noncorrosive, nontoxic to humans and able to circulate in refrigerators for years, even decades without breaking down, his discovery found wide application in refrigeration and eventually air conditioning. So safe were CFCs deemed that they were used in aerosol spray cans and even asthma inhalers.

For his work on CFCs Midgley received another award, the Perkin Medal from the Society of Chemical Industry in 1937.

If chemist F. Sherwood Rowland had not asked in the early 1970s where CFCs go once they are released, we might now be living without the better part of the Earth's ozone layer.

His work alerted the world that CFCs were indeed quite long-lived as advertised, were making their way continuously to the Earth's ozone layer and were systematically destroying it. Without the ozone layer much greater ultraviolet radiation would hit the Earth and endanger all living things. CFCs were ultimately banned by the Montreal Protocol.

Of course not. Pointing out potential and actual dangers of a specific application of scientific research in not anti-science at all.

In these cases we must remember that lots of people who called themselves scientists assured us that leaded gasoline and CFCs were safe. But, they were wrong, grievously wrong. And, we must remember that it took decades to uncover the widespread damage being done by both.

The U.S. Food and Drug Administration (FDA) long ago ruled that GMO foods are "substantially equivalent" to their non-GMO counterparts and therefore do NOT require any testing. Those supporting the widespread dissemination of GMOs could be very wrong as well. There isn't enough information to know what the ultimate results will be for human and animal health.

What is more interesting is that the authors of the petition mentioned above have essentially admitted that we are doing an uncontrolled experiment on humans (because governments required no controlled studies). They write:

But the science telling us GM [genetically modified] crops and foods are safe has been confirmed by vast experience. Humans have eaten hundreds of billions of GM based meals in the past 20 years without a single case of any problems resulting from GM.

The petition writers, of course, do not adduce any evidence that there has not been a single case of a problem with genetically engineered foods. They merely assert it. I would hazard a guess that they did not do an exhaustive survey to find any cases.

This leads us to the second claim that is supposed to prove that somebody is anti-science if he or she opposes GMOs.

2. There is no evidence that GMOs are harmful.
Anecdotal evidence and even some scientific studies suggest that GMOs may be harmful in one or more these three categories. Even if that evidence is valid, it begs the question, How harmful? Do the supposed benefits of GMOs outweigh any alleged or actual harm?

The problem with engaging assertion number 2 above is that it is an inversion of responsibility. The GMO industry and its supporters assume that it is the responsibility of the public to discover any harm and to document it sufficiently to prove that harm.

But the real responsibility ought to lie with the industry. Typically, the way this is done is that the government requires studies under controlled conditions to establish the safety of a product. Individual consumers and independent researchers don't have the financial and technical resources to do this.

If the industry wants to warrant that GMOs are safe for human consumption, it should have to follow protocols designed for novel products which it wants to introduce into the human body. These protocols are generally reserved for new drugs. But some scientists in the FDA suggested that just such protocols would be necessary to assure that GMOs are safe before their release to the public. (They were overruled.)

The industry assures us that GMOs are not novel. After all, the FDA ruled that GMOs are "substantially equivalent." On that basis all patents for GMOs crops would be invalid since they are not novel. But it is precisely based on the novelty of specific genetic alterations of plants that the GMO companies have successfully obtained patents on their products.

If GMO plants are indeed novel as the companies insist when they go to the patent office, then they ought to be obliged to prove they are safe under established protocols for novel products designed for human consumption.

Don't let the industry get away with this inversion of responsibility. Can the industry really make the claim that those who oppose GMOs because the foods derived form them are not properly tested are anti-science? Isn't the industry really anti-science for opposing the testing of novel foods in the same way the drug companies are obliged to test novel compounds? Isn't the industry being anti-science by claiming that GMOs are not novel? (Maybe that's just straight out lying.)

There is a third claim that is supposed to demonstrate that those who oppose GMOs are both anti-science and ignorant.

3. GMO crops are no more risky than crops by crossbreeding.
This is a clever argument indeed. For it tries to get the listener to accept the equivalence of the two types of genetic alteration. But they are not equivalent. And, the key reason is not the one cited most often by GMO critics, namely transgene splicing, the splicing of genes from completely different categories (from a fish to a tomato to cite a real example).

While it's theoretically possible for such gene transfers to take place in nature, they are highly unlikely. (How often is a fish in the wild going to come into contact with a tomato?)

What is more important is that humans have ample experience with crossbreeding. The fact that humans are still here in the numbers that they are testifies to the safety of crossbreeding which has been practiced for a very long time.

This does not testify to safety in every instance, but to safety in general. Historically, crossbred plants are tested in small areas to see whether thrive and to see how they interact with other plants. These small experiments keep any mistakes contained.

GMO crops on the other hand are poorly tested[1] and then introduced practically worldwide within a few years. If there is a hidden adverse interaction with the environment, we will be subject to worldwide effects before we are aware. Those effects might take years to become apparent. And, it might take us years to trace those effects to GMO crops. The adverse environmental effects of GMOs will not be contained. There will be no small mistakes.

Since our experience with GMOs is limited, there has been very little time to discover unintended consequences. The fact that GMO crops to date have not produced catastrophic systemic failures in farm fields or in the surrounding environment does not prove that the next new GMO crop won't produce such a failure or that existing GMO crops under some as yet unencountered situation won't produce such failures.

Now, here's the key point: Because we cannot from experience judge the risks of GMOs to the broader environment (as we can with crossbreeding), and we cannot anticipate all the interactions between GMOs and the environment, THERE IS A NONZERO RISK OF SYSTEMIC CATASTROPHE, namely, worldwide crop failure or systemic ruination of adjacent ecosystems.

The proponents will say that the risk of such systemic effects is small. But it does not matter how small that risk is if we intend to keep subjecting the environment to novel crop genes. If the risk is nonzero and we metaphorically pull the gene gun trigger enough times, we will eventually create systemic ruin.

We are playing a game of Russian roulette with the many genetic engineering techniques we are now employing. Techniques which have a nonzero risk of creating systemic ruin should be banned. Ruin is too great a price to pay no matter how big the perceived benefits are (and the supposed benefits of GMOs are hotly disputed).

Perhaps risk is not the purview of the pure scientist. But it certainly must be the purview of the applied scientist. To misunderstand risk in the worldwide dissemination of genetically novel crops is to set oneself up to be the next Thomas Midgley and to risk the lives and livelihoods of millions, even billions of people based on a mere feeling that what one is doing is low risk.

[1] The U.S. Department of Agriculture (USDA) requires field testing of GMO plants to determine whether they have the potential to harm other plants. The genetic contamination of non-GMO plants (through the exchange of pollen) which is prevalent worldwide seems of little concern to the USDA which seems not to regard this as a harm to other plants. This is particularly a problem for organic growers who are forbidden to use GMO crops and those conventional growers seeking non-GMO verification of their crops.

The FDA regulates as a pesticide any GMO plant which produces its own pesticide (as many of them do) and determines whether ingesting that pesticide in the amounts in the plant poses a hazard to human health--not particularly appetizing. A summary of these regulations can be found on p. 4 of this document.

• Kurt Cobb is an author, speaker, and columnist focusing on energy and the environment. He is a regular contributor to the Energy Voices section of The Christian Science Monitor and author of the peak-oil-themed novel Prelude. In addition, he has written columns for the Paris-based science news site Scitizen, and his work has been featured on Energy Bulletin (now Resilience.org), The Oil Drum, OilPrice.com, Econ Matters, Peak Oil Review, 321energy, Common Dreams, Le Monde Diplomatique and many other sites. He maintains a blog called Resource Insights and can be contacted at kurtcobb2001@yahoo.com.